Concrete form



June 12, 1951 J. W. M DONNELL CONCRETE FORM 2 Sheets-Sheet 1 Filed Aug. 9, 1948 F E J 7 June 12, 1951 w, MCDONNIELL 2,556,594

CONCRETE FoRM Filed Aug. 9, 1948 2 Sheets-Sheet 2 FlEi 4 \NVENTOR 74 ,JWMFDon me ATTORN EYS Patented June 12, 1951 CONCRETE FORM James W. McDonnell, Stanford, Calif.

Application August 9, 1948, Serial No. 43,227

Claims.

- This invention relates generally to forms for use in making concrete structures, and particularly cylindrical shaped structures such as are usable as manholes for subterranean electrical distribution systems.

It isI an object of the invention to provide a concrete; form which is usable for the purposes indicated above, and which in particular facilitates th' work of removing the walls of the form from the poured concrete after the concrete has hardened.

A further object of the invention is to provide a concrete form of the above character which can bje reused indefinitely, and which can be readily f positioned for a pouring operation, as well as readily removed after the concrete has hardened.

Another object of the invention is to provide,

a concrete form of the above character having both inner and outer metal walls, cylindrical in contour, and which is provided with means for effectively separating the walls from the sides of the concrete to facilitate removal after the concrete-has hardened.

Additional objects of the invention will appear from the following description in which the preferred embodiment has been set forth in detail in conjunction with the accompanying drawing.

Referring to the drawing:

Figure l is a side elevational view illustrating a concrete form incorporating the present invention.

Figure 2 is a cross-sectional view of the same form illustrated in Figure 1, but showing the parts disposed in an excavation ready for a pouring operation.

Figure 3 is a plan view of the form as illustrated in Figure 1, certain parts being broken away and certain parts being shown in section.

Figure 4 is an enlarged cross-sectional detail taken along the line 4-4 of Figure 1.

Figure 5 is an enlarged cross-sectional detail taken along the line 55 of Figure 1.

Figure 6 is an enlarged cross-sectional detail taken along the line 6--6 of Figure 1.

Referring first to Figures 1 to 3 inclusive, my form comprises inner and outer cylindrical metal walls II and 12, which are disposed in alignment to form the annular pouring space I3. Normally these walls are disposed in upright relation in an earth excavation I4 (Figure 2) to enable one to pour a circularly contoured annular wall.

The inner wall H can be formed of a single piece of steel bent into cylindrical form, and with an overlapping junction I6 for the adjacent 2 vertical edges. This junction can be formed by a vertical metal strip [1 which is secured as by welding to the adjacent edge 18 of the sheet" metal, and arranged to overlap the adjacent edge portion 19. Normally there is a substantial gap between the edge portions 18 and I9, topermit the wall II to contract somewhat by the. use of means to be presently described. 3;

Vertically disposed members 21, such steel angles, are attached to the wall II at circurnferentially spaced points as illustratedin Figure 3. At the lower end of the form there are two pairs of radially extending members 122 and 23, the two pairs being at right anglesto each other. The outer ends of these members are pivotally attached at 24 to the vertical members The inner ends of the members 22.;1and 23 have pivotal connections 26 with the lower end of a vertical member 21, which extendsf;axially of the form. At the upper end of the form similar radially extending members 28 :and 29 are provided, which have their outer ends pivotally attached at 3| to the upper ends of the vertical members 21, and their inner ends pivotally attached by pins 32 tothe vertical member 21. Similarly, intermediate the upper and lower ends of the form radially extending members 36 and 31 are provided, which are pivotally attached at 38 to the vertical members 2| and pivotally attached at 39 to the central vertical member 21. Near the upper end of the form, but below the members 28 and 29, cross-struts 4| and 42, are provided, which extend at right angles to each other and which are disposed immediately below the members 28 and 29. Members 41 and 42 are secured together by suitable means such as the bolt or rivet 43. The outer ends of the members 4i and 42 are connected to the corresponding ends of the members 28 and 29 by the links 44 and 46. Similar members 41 and 48 are provided below the members 36 and 31, and these members likewise connect with the outer ends of members 36 and 31, by the links 49 and 5|. The upper end of the member 21 is provided with a suitable hoist ring 52 for convenient attachment to a hoisting appliance. It will be evident that when the member 21 is pulled upwardly from the position shown in Figure 2, the inner ends of the members 28, 29, together with the members 22, 23 and 36, 31, will be moved upwardly, and as a result the outer ends of these members will pull inwardly on the vertical members 2|, and on the wall H to which these members are attached. As a result the inner wall is caused to collapse to the limit of the movement -wall sections.

3 permitted by the dimensioning of struts 4|, 42, 41 and 48. The amount of permitted contraction is such that it enables the inner wall II to be freed from hardened concrete, and to permit its removal.

The outer wall I2 is preferably made in a plurality of sections 211, I22), I20 and 12d. Sections Na and 1219 are attached together by special means to be presently described. The remainder of the sections are secured together by suitable means such as the upper and lower brackets 53 and 54, which are retained together by the clamping bolts 53 and 5'1.

Special means is provided to enable expansion of the outer wall l2, and preferably this means operates in conjunction with upward pull upon the vertical member 27. Thus a metal ring 58 is provided which generally embraces the upper part of the form, and which is made of suitable material such as a steel channel. Circumferentially spaced parts on this ring, .90" apart, are :loosely connected to the outer ends of the radially extending rods 6|. The inner ends of these rods are provided with eyes 53 which engage =the studs (it carried by the upper end of member 27. Circumferentially spaced points on the ring 58, intermediate the point of connection with rods 6|, are attached by pads 65 to intermediate points on the outer wall sections 12a, [21), 52c and 12d. The ring 58 has a certain amount of spring, so that when circumferentially spaced points on the same are sprung inwardly by in.- Iward pull exerted by rods St, the portions of the ring attached to pads 65 tend to spring outwardly to-thereby expand the outer form.

Additional means connecting the wall sections 12a and 12b enables these sections to be positively forcedapart when upward pull is applied to member 21. Thus connecting means is provided between thelower portions of wall sections We and 521), including the brackets "68, which are drilled to loosely accommodate theretaining bolt t2. Brackets 65 are yieldably urged together by the compression spring '58.

A vertical member 69 extends upwardly along the junction between the wall sections 12a and 121;, and this member may be a suitable structural steel channel as shown in Figure '5. It is pivotally attached at vertically spaced points H and T2,:tothe adjacent edges or the wall sectitons 12a and [227. These pivotal connections are two studs 73 and M (Figure 6) which in turn are mounted upon the adjacent edge portions of the With connections to the adjacent wallsections, as described, it will be evident that when the upper end of the member 69 is moved to the left, as viewed inFigure l, the'adjacent 'wall sections 62a and l2b will be forced away 'frc-meach other.

Camming means is associated with the upper eendzof member 69, and can be constructed as follows: An additional member 15, which may be in the form of a structural steel channel, is located near the upper end of member 63, but spaced outwardly from the same (see Figure 4). Spacer members ii are carried by znber 18, and engage the outer peripheral portion of the ring between the upper and lower flanges of the same. Apertures l8 and i9 are provided in the ring date the adjacent pull rod 8 l. The retaining nut 85 on red 6i engages the member 75 so that when rod 5! is pulled inwardly, member 1'6 applies inward thrust upon ring 5 8.

Extending. alongthe junction between the wall es and member 55 to looselyaccomosections I20. and iii), there is a vertical overlap strip 82, which is secured to wall 12a as by welding, and which extends in overlapping relation with the wall section [2b. Strip 82 and. the member 16 carry cam blocks 83 and 84 (Figure 5) which are provided with inclined cam faces 36 and 81. These cam blocks cooperate with cam blocks 83 and 88, which are mounted upon the member 69. H With the arrangement just described it will be evident that when member 16 is caused to move inwardly towardthe cam block 33, the two cam blocks 83 and 84 press upon the blocks 88 and. 89, to force the latter together with member 69 to the left as viewed in Figure 5. As previously pointed. out movement of the upper end of the member 59 to the left, as viewed in Figure 1, serves to force the two wall sections H20, and I22) apart.

The use of my concrete form can be explained as follows: It is installed in a ground excavation substantially as shown in Figure 2. If desired a can be used -.in order to insure proper density.

After the concrete has hardened the clamping bolts EB and 5? are loosened, .and suitable hoisting means is applied .to the ring 52. Thisring',

together with member 2?, is then lifted. Upward movement of member 2'! causes raisingof the members 23, 29, 3G, Ell and .22, .23 to contract the inner wall ii, thus breakingany adhesion between this wall and the concrete, and icon -;tractingthe inner wall to such dimensionsthat it may be readily removed. Contraction of the inner wall H is limited by engagement of this wall with the ends of the struts ii, t2 and, 48.

Upwardmovement of member 2'? also causes inward pull to be applied by the rods .6! tech-- cumferentially spaced points of theringfit. As previously p0 ed out these points spring in"- wardly, causi outward forces to be applied throughjpads'efi to expand the wall sections 12a,

i-2b,'l2c and i 2d. At the same time such-springing of the ring 58 moves the member 15 inward ly with the result that cam blccl: 84 moves toward cam block 83, thus shifting the upper end of membercb to the left as viewed in Figure 5, due to the camming action through theblocks-ilii and As previously explained such movement of the member as? acts through the pivotal connections 1i and E2 to positively force the wall sections l2a and i222 apart. 4

Upon completion of the operations described above all of the wall sections shouldbe detached from the concrete, whereby further upward pull upon the ring-" 2 serves to .elevate the form free of the poured structure. It should be understood however that conventional methods can'be used to assistbreaking any adhesion between the walls and the concrete, as for example applicationcf pneumatic hammers or the like.

It will be-seen from theforegoing'that I :have provided a complete form which provides both the outer and inner walls used in pouring a .cylin-i drical manhole. The arrangement is such that by --applying force to a single member, both'zthe inner and outer walls are detached from the hardened concrete, to permit removal of the form as a complete unit.

I claim:

1. In a concrete form construction, a substantially cylindrical shaped outer wall, said wall being provided with a longitudinally extendin junction permitting expansion of the wall, a longitudinally extending member exterior of said wall and extending along said junction, said member having vertically spaced points of pivotal connection to the wall sections adjacent said junction, and means for swinging said member about said pivotal connections to thereby expand said wall.

2. A form as in claim 1 in which said last named means comprises cam means acting between said member and said wall.

3. In a concrete form construction, a substantially cylindrical shaped outer wall, said wall being provided with a longitudinally extending junction formed to permit expansion of the wall, a member extending axially of said wall, and adapted to be moved longitudinally, a ring generally embracing the upper portion of said wall, means connecting circumferentially spaced points of said ring to sections of the wall, and means connecting other circumferentially spaced points of said ring to said centrally located memher, said other points being located intermediate said first named points on the ring, whereby longitudinal movement of said axially located member serves to spring portions of said ring inwardly and the other portions connected to the sections of the Wall to spring outwardly to there by expand the wall.

4. In a, concrete form construction, a substanstantially cylindrical shaped outer wall, said wall being provided with a longitudinally extending junction formed to permit expansion of the wall, a ring generally embracing the upper portion of the wall, means serving to connect circumferentially spaced points on said ring with sections of said wall, an axially located member movable longitudinally, pull rods connecting said axially located member with other circumferentially located points of said ring, said other points being located intermediate said first named points, a member extending generally longitudinally of the junction, said member having spaced points of pivotal connection with wall sections adjacent all) said junction whereby swinging of said member serves to move said wall sections apart, and cam means acting between said ring and one end portion of said member and serving to swing said member aboutsaid pivotal connections responsive to longitudinal movement of said first named member to spring the ring.

5. In a concrete form construction, inner and outer substantially cylindrical shaped walls spaced apart to form a pouring space, a member extending axially of said walls and adapted to be moved longitudinally upon application of forces to the same to lift the entire form, radially extending means connecting said member with said inner wall whereby longitudinal movement of said axiallylocated member serves to apply forces to contract the inner wall, means for limiting the extent of contraction or" the inner wall, a ring generally embracing the upper portion of the outer wall, means serving to attach circumferentially spaced points on said ring with circumferentially spaced points of the outer wall, means connecting said axially located member with other circumferentially spaced points of said ring, said other points being located intermediate said first named parts, pull upon said other parts serving to spring the ring from circular contour whereby the points connected with the Wall sections serve to expand the latter, a junction formed in the outer wall section and extending generally longitudinally of the same, said junction being formed to permit expansion of the wall sections adjacent the same, and additional means including cam elements serving to move said last named wall sections apart upon applying movement to said axially extending member to expand the inner wall and to spring said ring.

JAMES W. MCDONNELL.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 802,666 Stieler Oct. 24, 1905 825,052 Henry et al. July 3, 1906 874,366 Layfield et al Dec. 17, 1907 939,578 Wiltrout Nov. 9, 1909 1,336,867 Sloan Apr. 13, 1920 

